Intra- specific variation in response of Jatropha (Jatropha curcas L.) to elevated CO2 conditions.

Twenty genotypes of Jatropha collected from diverse eco-geographic regions from the states of Chhattisgarh (3), Andhra Pradesh (12), Rajasthan (4) and Uttarakhand (1) of India were subjected to elevated CO2 conditions. All the genotypes showed significant difference (p < 0.05 and 0.01) in the phenotypic traits in both the environments (elevated and ambient) and genotype x environment interaction. Among the physiological traits recorded, maximum photosynthetic rate was observed in IC565048 (48.8 μmol m(-2) s(-1)) under ambient controlled conditions while under elevated conditions maximum photosynthetic rate was observed in IC544678 (41.3 μmol m(-2) s(-1)), and there was no significant difference in the genotype x environment interaction. Stomatal conductance (Gs) emerged as the key factor as it recorded significant difference among the genotypes, between the environments and also genotype x environment interaction. The Gs and transpiration (E) recorded a significant decline in the genotypes under the elevated CO2 condition over the ambient control. Under elevated CO2 conditions, the minimum values recorded for Gs and E were 0.03 mmol m(-2) s(-1) and 0.59 mmol m(-2) s(-1) respectively in accession IC565039, while the maximum values for Gs and E were 1.8 mmol m(-2) s(-1) and 11.5 mmol m(-2) s(-1) as recorded in accession IC544678. The study resulted in the identification of potential climate ready genotypes viz. IC471314, IC544654, IC541634, IC544313, and IC471333 for future use.